So what does the service do? Well, it does what you might expect from a music app from Twitter -- it helps you find music that's popular on Twitter and music based on the bands you follow. The app is centered around four pages or tabs, which you can swipe through to access.

The Popular page shows you new music that's trending across Twitter while the Emerging tab shows "hidden talent found in tweets." While those two parts feed you information about what the collective Twitterverse is jaming to, the last two focus on who you follow and your personal music taste.

The Suggested tab shows artists you might like based on the artists you follow on the service and who they follow. And finally the #NowPlaying tab shows songs your friends are listening to or tweeting about. For instance, if your friend tweets that they are listening to a song by Justin Bieber, that song will show up on that page.

The iPhone app, which ABC News' Good Morning America got an early look at, has a clean and polished design. All the pages have a grid made up of artists and songs; tap one of those and the song willl start playing along with a fun spinning CD animation in the left corner. Tap on that and you get an enlarged CD -- you can drag your finger around the CD to fast forward or rewind within that song.

And the fact that you don't have to leave the app to listen might be one of the best parts. Twitter has integrated current music services like Rdio, Spotify and iTunes to allow you to play the songs right through the app or webpage. With iTunes, you will only hear a preview, but with Rdio and Spotify, users can log in with their accounts to hear the full tracks. Twitter says it will continue to work to add additional music providers to the app.

Twitter also put artists and bands at the center of the experience. You can go to artist's Twitter profile pages within the app and see what artists they follow and listen to. As Twitter says, it's like getting recommendations from your friends, except they happen to be music superstars. You can also search for artists through the search field and play a selection of songs from them.

Twitter announced last week that it had acquired "We Are Hunted," a music recommendation and streaming company based in Australia. Twitter also released Vine, a dedicated six-second video app, in January.

"There are times when you need a single-purpose driven knife in the kitchen and there are times when you are out camping and you want a swiss army knife. We have different apps for different purposes," Michael Sippey, Twitter's VP of Product, said earlier this week at the "All Things D: Dive into Mobile" conference when asked about the different apps Twitter has been releasing. Last week Facebook released Facebook Home for select Android phones. Home provides a Facebook experience deeper than an app.

The Twitter #Music app will be out later today in the Apple App Store; there is no Android app yet.